1. Field of the Invention
The present invention relates to a memory card, and more particularly, to a memory card having a flash memory and a method of storing data on the memory card.
2. Description of the Related Art
A memory card, may be used as an auxiliary memory for a digital device, such as a digital camera or a mobile phone. Examples of memory cards include compact flash (CF) cards, smart media (SM) cards, memory sticks, multimedia cards (MMC), microdrivers, an extreme digital (xD) picture cards and secure digital (SD) cards.
Memory cards are small in size, convenient to use and have high data transfer rates. For example, the xD picture card is a next-generation flash memory card that has been developed to address various size and capacity limitations of the SM cards. The xD picture card has dimensions of 20×25×1.7 mm, making it the smallest of the memory cards. The xD picture card is called “extreme digital” memory card because its storage capacity can be up to 8 GB (gigabytes).
The xD picture card is connected to a host (e.g., a digital camera) through an interface scheme for a NAND flash memory. The xD picture card can be smaller in size and increased in data storage capacity, as compared to other memory cards, such as a CF card, an SD card, a memory stick and an MMC, that use NAND flash memories.
In general, a memory card may include a NAND flash memory and a memory controller. The NAND flash memory stores data provided from a host. For example, when the host is a digital camera, still pictures are stored in the NAND flash memory. When the host is a camcorder, moving pictures are stored in the NAND flash memory. The memory controller controls overall operation of the memory card. Under the control of the memory controller, the data provided from the host are transferred to the NAND flash memory and the data stored in the NAND flash memory are output to the host.
The data storage time of the memory card is divided into the data transfer time from the host to the NAND flash memory and the program time of the NAND flash memory. The data transfer time is defined as the time taken for the memory controller to transfer data from the host to the NAND flash memory in response to a write request of the host. The program time of the NAND flash memory is defined as the time taken to program data, which have been transferred to the NAND flash memory, into a memory cell array of the NAND flash memory.
The reduction of the program time of the NAND flash memory is limited without fundamental changes in the NAND flash memory. However, it is possible to reduce the data transfer time from the host to the NAND flash memory in order to reduce the overall data storage time of the memory card.